1. Field of the Invention
The present invention relates to a semiconductor device having a wiring formed by silver bromide and a method of manufacturing the same and, more specifically, to a method of manufacturing a semiconductor device capable of easily, inexpensively forming a low-resistance wiring suitable for filling a via hole.
2. Description of the Related Art
FIGS. 1A to 1E show a process of manufacturing a semiconductor device wherein a diffusion layer formed on a silicon (Si) substrate and a metal wiring formed on a silicon oxide (SiO.sub.2) film are connected to each other through a via hole.
First a diffusion layer 2 is formed by diffusing impurities from the surface of a Si substrate 1, and then a SiO.sub.2 film 3 is deposited on the Si substrate 1 (FIG. 1A). Employing the PEP (Photo Engraving Process) and RIE (Reactive Ion Etching), a hole 4 is formed in the SiO.sub.2 film 3 so as to communicate with the diffusion layer 2 (FIG. 1B). The hole 4 is filled with a metallic material such as tungsten (W) by the CVD (Chemical vapor Deposition), resulting in a via hole 5 (FIG. 1C). After that, a wiring material such as aluminum (Al) is deposited on the SiO.sub.2 film 3 in which the via hole 5 is formed, thereby to form a wiring layer 6 (FIG. 1D). The wiring layer 6 is processed by the PEP and RIE to form a metal wiring 7 having a predetermined pattern (FIG. 1E).
However, the conventional method described above has a drawback of increasing the number of steps of forming the via hole 5 and metal wiring 7 and complicating the process of forming them, as shown in FIG. 2. It also has a drawback of increasing the resistance of the wiring since the tungsten (W) is used for forming the via hole 5 and is therefore unsuitable for forming a via hole having a high aspect ratio. To eliminate these drawbacks, it has been expected to develop a method capable of easily, inexpensively forming a wiring which is low in resistance and suitable for filling a via hole.